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Topic: Standard molar entropy

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Standard state

Standard enthalpy change of formation

Heat of fusion

Enthalpy

Entropy of fusion

Triple point

Potassium hydroxide

Titanium dioxide

Calorimeter

Ammonium chloride

Potassium nitrate

Methanol

Hydrazine

Calorimetry

Boric acid

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	Entropy
		Entropy is related to the energy distribution of energy states of a collection of molecules, and this aspect is usually discussed in statistical mechanics.
		Entropy is also related to probability, as a measure of randomness or disorder, and entropy is proportional to the logarithm of the probability.
		Since the entropies of most substances have been measured and tabulated in handbooks and data banks, standard entropies of reactions can be evaluated in a similar manner as enthalpies of reactions.
	www.science.uwaterloo.ca /~cchieh/cact/applychem/entropy.html (1585 words)

	Chapter 17 Review
		The standard molar entropy is simply the entropy of 1 mol of a pure substance at 1 atm pressure and standard temperature (usually 25°C).
		Both entropy and enthalpy considerations are combined in the term free energy change (abbreviated ΔG), which is the ultimate criterion for determining the spontaneity of a reaction.
		The standard free energy of formation of a substance measures its thermodynamic stability with respect to its constituent elements.
	www.msu.edu /~serordan/chap.17.htm (991 words)

	Entropy
		Entropy is defined as the degree of freedom that particles of matter have.
		The standard molar entropy of a substance is entropy value of the substance at stanard state.
		Standard state is defined as 1 Molar for any aqueous ion, 25 degrees Celsius and a pressure of 1 atm.
	members.aol.com /profchm/entropy.html (1491 words)

	Standard molar entropy - Wikipedia, the free encyclopedia
		In chemistry, the standard molar entropy is the entropy content of one mole of substance, under conditions of standard temperature and pressure.
		By comparing the entropies S and enthalpies H of products and reactants in a chemical reaction, we can determine whether the reaction will go forward or backwards.
		The standard molar entropy is usually given the symbol S
	en.wikipedia.org /wiki/Standard_molar_entropy (140 words)

	Entropy in General Chemistry
		Entropy (or better, entropy change) is the quantitative measure of that kind of a spontaneous process: how much energy has been transferred/T or how widely it has become spread out at a specific temperature.
		Entropy in a heating process is just a measure of the motional energy of molecules from hotter surroundings being transferred (reversibly) to a cooler system divided by the T at which it is transferred.
		That last type of entropy change is surely one of the most important in general chemistry because it is the cause of colligative effects such as the raising of boiling points and depression of freezing points of solvents, as well as of osmosis.
	www.entropysite.com /wiki_entropy.html (4637 words)

	New Recommendations 4.2-4.4
		is the standard enthalpy for the dissociation of the magnesium complex formed with the buffer.
		The adjustment of standard formation properties of species to standard transformed formation properties at the desired pH and pMg has been mentioned in connection with Table II.
		It is also recognized that while a standard state based upon the concentration scale has been widely used in biochemistry, the molality scale has significant advantages for many purposes and can also be used for the study of biochemical reactions and for the calculation of thermodynamic properties.
	www.chem.qmul.ac.uk /iubmb/thermod/th42.html (2686 words)

	E - Glossary of chemical terms
		Electrode potential is defined as the potential of a cell consisting of the electrode in question acting as a cathode and the standard hydrogen electrode acting as an anode.
		Entropy (S) is a measure of the unavailability of a system's energy to do work; in a closed system, an increase in entropy is accompanied by a decrease in energy availability.
		When a system undergoes a reversible change the entropy (S) changes by an amount equal to the energy (Q) transferred to the system by heat divided by the thermodynamic temperature (T) at which this occurs.
	www.ktf-split.hr /periodni/en/abc/e.html (1731 words)

	Chapter 19
		The amount of entropy a substance has is the amount of structure which needs to be broken down to convert substance from perfect structure (zero K crystal) into its current state.
		Whenever an increase in entropy in one process is associated with a decrease in entropy in another, the increase in entropy has to dominate in order for the overall change to be spontaneous (second law of thermodynamics).
		Standard molar entropies of elements are not zero because absolute entropies are zero only at 0 K and "standard state" means room temperature (298 K).
	www.chem.lsu.edu /htdocs/people/jchogan/CHEM_1202/Notes/Chapter_19.html (1838 words)

	EntrCalc (Site not responding. Last check: )
		We have seen that the energy given off (or absorbed) by a reaction, and monitored by noting the change in temperature of the surroundings, can be used to determine the enthalpy of a reaction (e.g.
		Standard molar entropies are listed for a reference temperature (like 298K) and 1 atm pressure (i.e.
		Unlike enthalpies of formation, standard molar entropies of elements are not 0.
	wine1.sb.fsu.edu /chm1046/notes/Thermody/EntrCalc/EntrCalc.htm (601 words)

	Solid adsorbent/gas interface: characteristic thermodynamic quantities of adsorption
		Changes in enthalpy and entropy associated with adsorption are usually attributed to changes in the thermodynamic state of the adsorbate only.
		is the standard differential molar enthalpy of adsorption.
		The standard integral molar entropy of adsorption is
	www.iupac.org /reports/2001/colloid_2001/manual_of_s_and_t/node31.html (377 words)

	Standard-state entropies
		The utility of the third law (which is more of a definition) is that absolute entropies can be defined with respect to the reference state it provides.
		Thus, the standard molar entropy of a substance is defined to be the entropy change between 0 K and 298.15 K (25
		In analogy with the choice made for standard enthalpies of formation, the standard molar entropy of H
	nyu.edu /classes/tuckerman/honors.chem/lectures/lecture_18/node3.html (120 words)

	Thermo Notes for Chapter 20 (Site not responding. Last check: )
		We will often be using the standard molar entropy at 298 Kelvins, note the units of J/mol K. Note, Joules, not kilojoules as for the enthalpies.
		Entropies of more complex molecules are larger than those of simpler molecules in closely related compounds.
		Now, you could calculate the entropy change for the universe to determine whether or not a reaction is considered spontaneous or not.
	chemweb.calpoly.edu /chem/maxwell/124f00thermonotes2.html (1128 words)

	Standard-state entropies
		The utility of the third law (which is more of a definition) is that absolute entropies can be defined with respect to the reference state it provides.
		Thus, the standard molar entropy of a substance is defined to be the entropy change between 0 K and 298.15 K (25
		In analogy with the choice made for standard enthalpies of formation, the standard molar entropy of H
	www.nyu.edu /classes/tuckerman/honors.chem/lectures/lecture_18/node3.html (128 words)

	welcome to entropysite.com
		It dealt with the general topic of considering entropy as a measure of the dispersal of energy at T. A new subtopic was “Clarification of the meaning of `configurational' entropy: a measure of energy dispersal in statistical mechanics calculations”.
		"Entropy is disorder" is an archaic, misleading definition of entropy dating from the late 19th century before knowledge of molecular behavior, of quantum mechanics and molecular energy levels, or of the Third Law of thermodynamics.
		Entropy may be the most feared topic in beginning university chemistry —; by students because of its complexity, by instructors because students fail to understand its basic principles.
	www.entropysite.com (5071 words)

	[No title]
		We define the standard state as for a mole of particles at 1 atm pressure (to take account of the changes in energy level separation for the translational energy of gases when the volume changes).
		Standard molar entropies increase in the order solid, liquid, gas for any real substance, For gases, increasing mass leads to increasing standard molar entropy.
		One trend that is tricky to explain involves the unusually high standard molar entropy of O2.
	www.stolaf.edu /depts/chemistry/imt/days/day14.doc (307 words)

	Defintion of entropy, the measure of randomness, from ChemicalFacts.com. (Site not responding. Last check: )
		Defintion of entropy, the measure of randomness, from ChemicalFacts.com.
		The entropy of a chemical substance is a thermodynamic state function that measures the randomness or disorder of the system.
		The entropy change is a positive because the reaction produces one mole of gas.
	www.chemicalfacts.com /definition/entropy.html (644 words)

	S
		The entropy of the universe increases in a spontaneous process and remains unchanged in an equilibrium process.
		The sum of the standard reduction potential of the substance that undergoes reduction and the oxidation potential of the substance that undergoes oxidation.
		The entropy of 1 mol of a substance in its standard state.
	www.mhhe.com /physsci/chemistry/chang7/esp/tools/glossary/glossary_files/s.htm (875 words)

	chap18lec2.html (Site not responding. Last check: )
		The entropy of a perfect crystal at 0 K is zero.
		Standard molar entropy, S°: the entropy of a substance
		For a spontaneous reaction, the entropy of the universe
	andromeda.rutgers.edu /~rogerlal/chem116/chap18lec2.html (369 words)

	Chemistry Film Studio
		The value for the standard molar entropy of ammonium dichromate has been estimated by Latimer's rules, which state that the entropy of each atom of each element in a compound in JK mol
		is the relative atomic mass of the element and R is the gas constant) and that the entropy of a compound is the sum of the entopies of all elements in the compound.
		This rule may be found useful for estimating the entropies of other compounds which are not readily available in the literature.
	neon.chem.ox.ac.uk /vrchemistry/FilmStudio/volcano/HTML/page02.htm (100 words)

	General Chemistry Online: Glossary: Energy and chemical change
		The heat required to raise the temperature of one mole of a substance by 1°C is called the molar heat capacity of the substance.
		The molar heat capacity of elements is sometimes called the "atomic heat capacity".
		The standard state for liquids and solids is the state of the most stable form of the substance at the standard pressure.
	antoine.frostburg.edu /chem/senese/101/thermo/glossary.shtml (1938 words)

	General Chemistry Online: Glossary:
		The standard deviation is a statistical measure of precision.
		The standard state for a gas is the the state of the pure substance in the gaseous phase at the standard pressure
		Standard pressure is a pressure of 1 bar.
	antoine.frostburg.edu /chem/senese/101/glossary/s.shtml (2542 words)

	Foundations to Chemistry - adapted from "Chemistry, Matter and the Universe"
		In many reactions the contributions of enthalpy and entropy (disorder) reinforce one another, as in the arrow diagram at the upper right.
		Enthalpy applies 3.62 kcal worth of opposition to the dissolving of ammonium chloride in water, but entropy, or disorder, favors the dissolving process by 5.25 kcal.
		The key to chemical spontaneity is not what enthalpy or entropy may do individually, but what happens to the free energy during the process.
	www.chem.ox.ac.uk /vrchemistry/entropy/page29.htm (322 words)

	Clark State - Academic Programs
		Using standard molar entropy values to calculate the standard molar entropy of reaction.
		Using standard free energies of formation to calculate standard free energy changes for reactions.
		Calculating standard potential of a galvanic cell from standard reduction potentials for the anode and cathode.
	www.clark.cc.oh.us /syllabus_cgi.html?CHM123S (2282 words)

	18. The Gibbs Free Energy (Site not responding. Last check: )
		There is nothing in the laws of mechanics that states says that at a later time, the water molecules cannot suddenly all give up their kinetic energy to the cold nickel sample and warm it back up again.
		The standard enthalpy of formation of CO is easily measured because graphite and oxygen gas are in their standard states:
		As with the enthalpy, the standard Gibbs free energy of formation for a chemical element in its standard state is 0.
	scholar.chem.nyu.edu /0109/suppnotes/tuckerman/node19.html (2653 words)

	Organic Compounds: Physical and Chemical Data (Site not responding. Last check: )
		Standard molar enthalpy change of combustion at 298 K
		Standard molar Gibbs free energy change of formation at 298 K
		Standard molar entropy at 298 K. Chosen standard pressure is 1 atm
	www.ucdsb.on.ca /tiss/stretton/Database/organic_thermo.htm (41 words)

	notes17
		From tables of entropy values it can be seen that there is more entropy or “energy of disorder” when thermal or positional disorder is increased such as when:
		The second law of thermodynamics states that: the total entropy of the universe is always increasing.
		Standard state conditions for entropy are 1.00 atm and 298 K. A table of standard molar entropy values is in the appendix and has values in Joules/K*moles.
	nsm1.nsm.iup.edu /woolcock/CH112Lec/notes17.htm (434 words)

	Entropy and Free Energy
		The degree of disorder or randomness of a substance is measured by its entropy
		Entropy and entropy changes refer to the number of ways of arranging atoms, molecules or ions in a system.
		Standard conditions are 298K, 100000 Pa (Nm), and 1 mole.
	www.avogadro.co.uk /h_and_s/entropy.htm (1680 words)

	CHM1045 (Site not responding. Last check: )
		The entropy of the ions decrease as the form the solid
		Is the reaction favored, or disfavored, with regard to the standard molar entropy change?
		Thus, the reaction is disfavored with regard to the standard molar entropy change.
	wine1.sb.fsu.edu /chm1046/homework/hmw07/hmw07key.htm (662 words)

	Speed of sound -- Facts, Info, and Encyclopedia article (Site not responding. Last check: )
		In the (A unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade) standard atmosphere:
		In fact, assuming an (A hypothetical gas with molecules of negligible size that exert no intermolecular forces) ideal gas, the speed of sound depends on temperature only, not on the pressure.
		The temperature of the air varies with altitude, giving the following variations in the speed of sound using the standard atmosphere (actual conditions may vary).
	www.absoluteastronomy.com /encyclopedia/s/sp/speed_of_sound.htm (1164 words)

	A Student’s Approach to the Second Law and Entropy
		Entropy measures the spontaneous dispersal of energy: how much energy is spread out in a process, or how widely spread out it becomes — at a specific temperature.
		Even though our simple predictions based on energy dispersal always works, technically and fundamentally, entropy change requires both the presence of molecules that have motional energy and also calculations that show that it is more probable for such particles to be in two rather than one volume.
		Then also, it is obvous that the entropy will be larger depending on how many molecules of solute are added to the solvent.
	www.entropysite.com /students_approach.html (2516 words)

	chap18lec2.html
		The entropy of a perfect crystal at 0 K is zero.
		Standard molar entropy, S°: the entropy of a substance
		For a spontaneous reaction, the entropy of the universe
	newark.rutgers.edu /~jimms/chap18lec2.html (369 words)

	Chapter 17 Notes
		Each molecule or ion is in a particular location and orientation within the crystal "lattice." Yet, the entropy of solids is not zero, because the molecules (or ions) within the crystal have some "thermal motion," which means they are wiggling around within their confined location in the lattice.
		Thus, the change in Entropy and Enthalpy of the System alone will allow us to decide if the change in Entropy of the Universe is positive or negative, and therefore if the reaction in the System is spontaneous or not.
		Then we calculate the changes in enthalpy and entropy from the enthalpies of formation and the standard molar entropies.
	www.chem.vt.edu /chem-dept/deck/1036/notes_17.html (2354 words)

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